Good link. I think it just proves that you can't trust the competitors to defend your personal information either.
In the end, no one will defend your important documents more than you will, and that's why I doubt Google Docs will ever gain much market share in the enterprise sector until the day they allow it to be hosted on the intranet (like they do for their corporate search service).
For small businesses it might be an interesting solution though. I think most people don't know much about security in general (not just computers), so hosting things on a Google server might be better than on your spyware ridden home office computer.